Sternotomy results in chronic postoperative pain in 30-55% of subjects. Few studies have been published on chronic pain in cardiac surgery, but there appears to be a relationship between the area of peri-scar hyperalgesia, which is indicative of postoperative hyperalgesia, and the occurrence of persistent pain 6 months after surgery. The aim of this study was therefore to assess whether the area of the postoperative hyperalgesia zone predicts chronic pain at 3 months post-surgery in cardiac surgery. To define the area of hyperalgesia at Day 2, pain mapping (algocartography) will be performed in patients who have had a sternotomy in cardiac surgery, together with pain assessment using the Simple Digital Pain Scale. Von Frey filaments of different sizes will be used for mapping. At Day 90, additional quality-of-life questionnaires will be carried out to check whether chronic pain is still present. A simple numerical scale (ENS) assessment at rest and during activity, and a record of pain-relieving treatments related to the surgery will also be carried out during this call. The investigators hypothesize that the area of the zone of hyperalgesia assessed at Day 2 predicts the occurrence of chronic pain at 3 months.